My CF4 charges to 4.16v if I switch it off and let it charge, and charges to 4.15v if its on and I use it whilst its charging (pass through)
this is my first mod box, but by far not my first use of charging LiPo batteries, I also fly very high powered professional RC helicopters, those use 6 cell 22.2volt LiPo's and require a balance charger, they charge to 4.2v per cell, but in my experience, using them and charging them all the time (each battery only last 10mins of flight) they begin to swell up, thankfully that is a swelling you can see, I would hate to think what would happen if that same swelling happened inside my CF4 without me knowing, when these RC batteries swell, its time to dig a hole in the garden and burry it for 6 months before disposing of it, otherwise, continued use and its bye bye £1000 heli in a ball of flames, ive posted a picture below of the swelling I'm talking about, both in a mobile phone and an RC heli Lipo, great battery invention, extremely dangerous though, 4.15v to me is a safety thing not a fault.
And this is caused from full charging and discharging all the time: